Mylan & Biocon v. Regeneron: Aflibercept Biosimilar Appeal Voluntarily Dismissed
Mylan NV and Biocon Biologics brought a Federal Circuit appeal against Regeneron Pharmaceuticals targeting 13 patents covering aflibercept anti-VEGF biologics — spanning manufacturing, formulation, and CHO cell expression. The parties agreed to dismiss the appeal after 295 days, with each side bearing its own costs, leaving the underlying merits unresolved.
A 13-Patent Biosimilar Appeal Ends Without Federal Circuit Merits Review
Mylan NV and Biocon Biologics filed this Federal Circuit appeal on 25 June 2024, challenging Regeneron Pharmaceuticals across 13 US patents protecting the aflibercept biologic — sold by Regeneron as Eylea — covering anti-VEGF protein compositions, CHO cell integration sites, biological contaminant detection, chemically defined manufacturing media, and intravitreal formulation. The case arose from infringement proceedings related to Mylan and Biocon’s biosimilar development programme.
On 16 April 2025, the parties jointly agreed to dismiss the appeal under Federal Rule of Appellate Procedure 42(b), with each side bearing its own costs. This procedural mechanism allows parties to terminate an appeal by stipulation before the appellate court issues any substantive ruling, meaning the Federal Circuit rendered no opinion on the validity or infringement of any of the 13 asserted patents. The public record does not disclose whether the dismissal was with or without prejudice to the underlying claims.
The 295-day duration and the symmetric cost arrangement — neither party recovering fees — is consistent with a negotiated resolution or commercial agreement reached outside the court record, though the public filing does not confirm this. What drove the parties to withdraw before merits adjudication remains unknown. The breadth of patents at stake, spanning upstream manufacturing to final ophthalmic formulation, suggests that any commercial resolution, if one occurred, would carry significant implications for the aflibercept biosimilar competitive landscape.
Filing to Voluntary dismissal in 295 days
295-day appeal — resolved before Federal Circuit merits briefing completed
Voluntarily dismissed: what the Fed. R. App. P. 42(b) order means for both parties
Fed. R. App. P. 42(b): appeal ends by party agreement
Under Federal Rule of Appellate Procedure 42(b), parties may stipulate to dismiss a pending appeal before the court issues a merits decision. The Federal Circuit here granted that stipulation, terminating the case without examining the validity or infringement of any of the 13 asserted patents. No precedential or non-precedential opinion was issued. The legal positions of both parties remain formally untested at the appellate level.
No merits adjudicationWith or without prejudice? The public record is silent
A voluntary dismissal under Rule 42(b) can be entered with or without prejudice to refiling, but the order here specifies only that the appeal is dismissed — it does not state whether Mylan and Biocon are barred from reasserting related claims. This distinction matters significantly: a without-prejudice dismissal preserves future challenge options; a with-prejudice dismissal forecloses them. The public filing does not resolve this, and practitioners should not assume either outcome.
Prejudice status unknownMylan and Biocon exit without a Federal Circuit ruling in their favour
By dismissing the appeal, Mylan and Biocon forgo any opportunity to obtain a Federal Circuit ruling that could have narrowed or invalidated Regeneron’s 13-patent portfolio. Any gains from the underlying district court proceedings that were appealed remain in place. If the dismissal reflects a negotiated arrangement, biosimilar commercialisation terms may have been addressed privately — but the public record does not confirm this.
No appellate relief obtainedRegeneron’s 13-patent portfolio survives appellate challenge unchallenged
For Regeneron, the dismissal means none of the 13 aflibercept patents — spanning manufacturing, formulation, CHO expression, and VEGF antagonist use — were invalidated or narrowed at the Federal Circuit. The patent portfolio emerges from this proceeding formally intact. However, the absence of a merits ruling also means Regeneron did not secure precedential appellate authority affirming its patents, which could matter if future biosimilar challengers mount fresh proceedings.
Portfolio survives intactFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Mylan, NV | Company | Biosimilar developer — co-holder of appeal over 13 aflibercept-related US patentsSearch in Eureka ↗ |
| Co-Plaintiff | Biocon Biologics, Inc. | Company | Search in Eureka ↗ |
| Defendant | Regeneron Pharmaceuticals, Inc. | Company | Regeneron Pharmaceuticals — originator and patent holder for Eylea (aflibercept) anti-VEGF biologicSearch in Eureka ↗ |
| Plaintiff counsel | Deanne M. Mazzochi | Attorney | Counsel for Mylan, NVSearch in Eureka ↗ |
| Plaintiff counsel | Eric R. Hunt | Attorney | Counsel for Mylan, NVSearch in Eureka ↗ |
| Plaintiff counsel | Heinz Johann Salmen | Attorney | Counsel for Mylan, NVSearch in Eureka ↗ |
| Plaintiff counsel | Lauren Marie Lesko | Attorney | Counsel for Mylan, NVSearch in Eureka ↗ |
| Plaintiff counsel | Neil McLaughlin Litigation Counsel | Attorney | Counsel for Mylan, NVSearch in Eureka ↗ |
| Plaintiff counsel | Paul J. Molino | Attorney | Counsel for Mylan, NVSearch in Eureka ↗ |
| Plaintiff counsel | William A. Rakoczy | Attorney | Counsel for Mylan, NVSearch in Eureka ↗ |
| Plaintiff law firm | Rakoczy, Molino, Mazzochi, Siwik LLP | Law Firm | Representing Mylan, NVSearch in Eureka ↗ |
| Defendant counsel | Adam Pan | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Andrew V. Trask | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Arthur John Argall, III | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Christian GladdenSorensen | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | David I. Berl | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Elizabeth Weiswasser | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Jacob Hartman | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Kathryn Schleckser Kayali | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Priyata Patel At | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Rhochelle Krawetz | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Shaun Patrick Mahaffy | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Thomas S. Fletcher | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant law firm | Kellogg, Hansen, Todd, Figel & Frederick, PLLC | Law Firm | Representing Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant law firm | Paul, Weiss, Rifkind, Wharton & Garrison LLP | Law Firm | Representing Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant law firm | Williams & Connolly LLP | Law Firm | Representing Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The dismissal order is terse by design: it records party agreement, invokes Rule 42(b), and allocates costs symmetrically. Critically, it contains no merits language — no claim construction, no validity finding, no infringement ruling. At the appellate level, a Rule 42(b) stipulated dismissal means the Federal Circuit never applied its standard of review to the district court record. The equal cost allocation departs from the norm where a losing party bears costs, which suggests the dismissal reflects a mutual commercial decision rather than either party conceding on the underlying patent disputes.
US9222106B2 and 12 further patents — aflibercept biologics portfolio
The 13 patents at issue collectively define a layered IP estate protecting Regeneron’s aflibercept biologic (Eylea) from molecule to market. The portfolio spans anti-VEGF protein composition claims, CHO cell line integration sites used in upstream manufacturing, chemically defined production media designed to minimise aflibercept variants, biological contaminant detection methods, and intravitreal formulation claims targeting ophthalmic delivery. Application filing dates across the portfolio span from 2013 through 2021, reflecting a prosecution strategy that continuously refreshed patent coverage as the manufacturing process matured.
Strategically, this portfolio exemplifies how an originator biologic company can construct overlapping layers of IP across the full manufacturing and delivery value chain — complicating any biosimilar applicant’s ability to design around any single patent without potentially encountering others. For competitors developing aflibercept biosimilars, the breadth of process-level patents (CHO expression, media composition, variant reduction) means process design changes must be evaluated against multiple independent patent families, not just the core composition patents. This case signals that Regeneron is prepared to assert the full breadth of this estate in litigation.
Should your team run an FTO against Regeneron’s aflibercept patent estate?
Any company developing, manufacturing, or commercialising an aflibercept biosimilar — or a biologic using CHO-based expression systems with anti-VEGF fusion proteins — should treat this 13-patent portfolio as a priority FTO target. The patents at stake here are not limited to the drug molecule; they reach into upstream CHO cell line selection, media formulation, contaminant assay methods, and downstream fill-finish for intravitreal use. Exposure can arise at any stage of the manufacturing workflow, not just at the point of product sale.
PatSnap Eureka’s FTO Search Agent can map your specific manufacturing process steps against each of the 13 asserted patents, identify claim scope, flag dependent claims with narrower coverage, and surface prior art that may support invalidity arguments. For biosimilar teams working on Eylea reference product applications, Eureka can also track Regeneron’s broader prosecution activity to anticipate continuation filings that may extend this estate further.
Run a freedom-to-operate analysis on US9222106B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit biosimilar patent appeals involving anti-VEGF biologics
Explore related Federal Circuit appeals involving biosimilar patent disputes over anti-VEGF biologics, CHO manufacturing processes, and ophthalmic biologic formulations.
What this case signals for the aflibercept biosimilar IP landscape
A 13-patent Federal Circuit appeal withdrawn by stipulation raises pointed questions for biosimilar developers and biologics originators alike.
Depth of Regeneron’s aflibercept patent thicket warrants early FTO analysis
With 13 patents asserted spanning upstream CHO manufacturing, expression optimisation, contaminant detection, and intravitreal formulation, Regeneron’s IP estate around aflibercept is exceptionally broad. Any biosimilar developer entering this space should model the full patent thicket — not just the core composition patents — before committing to manufacturing process design.
Mutual cost-bearing order is consistent with a negotiated commercial exit
When both sides agree to bear their own costs in a voluntary Federal Circuit dismissal, this pattern typically suggests the dispute was resolved through a deal rather than one party capitulating. Biosimilar market participants should monitor Mylan/Biocon’s Eylea biosimilar commercial activity for signs of a licensed or delayed-entry agreement with Regeneron.
Mylan v Regeneron — key questions answered
The Federal Circuit appeal (Case 24-2002) brought by Mylan NV and Biocon Biologics against Regeneron Pharmaceuticals over 13 aflibercept patents was voluntarily dismissed on 16 April 2025 under Fed. R. App. P. 42(b). The parties agreed to dismiss with each side bearing its own costs. No merits ruling was issued by the Federal Circuit.
The appeal involved 13 US patents held by Regeneron: US9222106B2, US11084865B2, US9816110B2, US11253572B2, US10415055B2, US10669594B2, US10888601B2, US10130681B2, US10464992B2, US11066458B2, US9254338B2, US11306135B2, and US11104715B2. These patents cover aflibercept protein compositions, CHO cell expression, manufacturing processes, and intravitreal formulations.
A Rule 42(b) voluntary dismissal means the Federal Circuit issued no ruling on the validity or infringement of any of the 13 patents. The patents are neither invalidated nor adjudicated as infringed. The public order does not specify whether the dismissal is with or without prejudice, leaving the status of any future challenge legally ambiguous based on the public record alone.
The order that each side bear its own costs is consistent with a negotiated commercial resolution rather than one party conceding defeat — in contested dismissals, costs typically follow the outcome. However, the public record does not confirm a settlement or licensing agreement. Market participants should monitor biosimilar regulatory filings and Mylan/Biocon commercial activity for signals of any underlying deal.
Regeneron’s 13-patent estate covers not just the aflibercept molecule but also CHO cell integration methods, chemically defined manufacturing media, variant reduction, contaminant detection, and intravitreal formulation. Biosimilar developers face potential infringement exposure at multiple manufacturing and formulation stages, not merely at the composition level. A comprehensive FTO analysis across all 13 patent families — and monitoring of continuation filings — is advisable before advancing any aflibercept biosimilar programme.
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